Tensor Charge of the Nucleon on the Lattice

Tensor charge of the nucleon, which will be measured in Drell-Yan processes in polarized proton-proton collisions at RHIC, are studied in quenched lattice QCD simulation. On the 16$^3\times$ 20 lattice with $\beta=5.7$, connected parts of the tensor charge are determined with small statistical error, while the disconnected parts are found to be small with relatively large error bars. Flavor-singlet tensor charge ($\delta \Sigma = \delta u + \delta d + \delta s$) is not suppressed as opposed to the flavor singlet axial charge ($\Delta \Sigma = \Delta u + \Delta d + \Delta s$).